Application of the compatibility factor to the design of segmented and cascaded thermoelectric generators

Abstract

Using thermoelectric compatibility, efficient thermoelectric generators are rationally designed. With examples, compatible and incompatible systems are explained and materials proposed for targeted development. The compatibility factor explains why segmentation of (AgSbTe2)0.15(GeTe)0.85 (TAGS) with SnTe or PbTe produces little extra power, while filled skutterudite increases the efficiency from 10.5% to 13.6%. High efficiency generators are designed with compatible n-type La2Te3, and similar p-type material, while incompatible SiGe alloys actually reduce the efficiency. A refractory metal with high p-type thermopower (>100 μV/K) is required for development. Cascaded generators avoid the compatibility problem. The thermoelectric potential provides a simple derivation of the cascading ratio.